In these moves and others, there is a strong whiff of rent-seeking gamesmanship, that is, companies wielding patent claims as a tax on their rivals, to slow them down.

Google, the ascendant newcomer in the smartphone market, may or may not have played fast and loose with the intellectual property of others. But when David Drummond, Google’s chief legal officer, points out that a modern smartphone can be a magnet for as many as 250,000 patent claims, it is not to agree that many of them are “dubious patents.”

That’s mainly the world of software patents. It’s a mess, for all sorts of reasons.

But a recent conversation with James Dyson, the British designer and engineer, pointed to another side of patents — their value, economic necessity and the need for principled enforcement.

Mr. Dyson, 64, is best known as the designer and entrepreneur behind some remarkably stylish and inventive household appliances, notably the bagless, cyclonic Dyson vacuum cleaner and the Dyson bladeless “air multiplier” fan.

The fan, introduced in 2009, has been a particular favorite of product pirates, with about 100 copycat models surfacing in 20 countries. Dyson spends many millions a year pursuing the pirates.

China, Mr. Dyson says, is a particular problem, not only because of the pirates but because of its patent policies. Under World Trade Organization rules, domestic and foreign companies, in theory, are to be treated the same. “China is clearly not doing that at the moment,” he said in an interview.

In China, Mr. Dyson says, it typically takes four or five years for a foreign company to get a patent approved. Domestic filers, he noted, usually get their patents approved in nine months or so, and they receive a $15,000 incentive payment from the Chinese government, which wants China to become a global patent power.

The lag in patent approval for foreign companies, Mr. Dyson said, makes it difficult to get at pirate producers in China, since there may be no approved patents to enforce.

Mr. Dyson is an adviser to the government of David Cameron, and the British government has brought the issue up in trade talks with China. But no actions have been taken yet.

“Obviously, intellectual property should be upheld globally,” Mr. Dyson said. “And policing intellectual property is an important part of that.”

So instead, Dyson often pursues the retailers and importers in other countries. There have been some successes. In July, Dyson won a judgement in Germany against a retailer there, Plus Online. The retailer had to stop selling the fans, and about 350 copycat fans were seized and destroyed.

Mr. Dyson estimates that one-third of his company’s costs go into research and development. “It’s our lifeblood,” he said, “because we can’t be the lower-cost producer.”

“But you can only pay for it if there’s a payback,” he observed. “And you can only charge more if you have something they don’t.”